ANIMAL MODELS FACILITIES CORE: PROJECT SUMMARY/ABSTRACT Animals continue to be important models for the study of molecular mechanisms of complex biological processes related to environmental exposures. The AMFC provides and maintains genetically engineered mice that are increasingly being generated to model specific aspects of human diseases and have proven to be extremely valuable in examining how genetic alterations interact with environmental chemicals and microorganisms to induce disease. Having personnel with this expertise as well as centralized laboratory equipment will provide critically important resources for the CEHS. The overall objective of the Animal Models Facilities Core (AMFC) is to provide Center members with state-of-the-art pathology support, transgenic resources and a centrally managed AAALAC-accredited animal resource and surgical facility. The Core is staffed with experienced personnel and is equipped with essential equipment to generate genetically engineered mice, rederive imported mice by embryo transfer rederivation, provide colony management, utilize gnotobiotic technology, develop surgical models and prepare and interpret tissue samples by histological and immunohistochemistry analysis. The CEHS will continue to rely heavily on animal models, particularly genetically engineered mice (GEM). The models being used by Center members will require extensive characterization of their tissue phenotypes. Both the technical aspects of obtaining excellent quality sections and expertise in the identification of pathological changes are essential for the discovery of meaningful genetic and epigenetic changes that are responsible for the development of lesions. Unfortunately, this histopathologic expertise is not always available to biomedical research groups and, when absent, can lead to the misinterpretation of data. Under the direction of Professor Fox, who is boarded in laboratory animal medicine with 40 years? experience, and an additional five boarded DVMs and two board certified veterinary pathologists and a fully staffed diagnostic and histology laboratory, the AMFC will provide essential transgenic, embryo transfer derivation, colony management, germ free technology, histology, pathology and clinopathologic services that will enhance the research programs of Center members.